JP3478790B2 - Image reading device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus having a structure for moving an illuminating optical moving frame and a reflecting optical moving frame by a drive motor.

[0002]

2. Description of the Related Art In image forming apparatuses such as copying machines, image reading apparatuses for reading a document placed on a contact transparent glass plate are well known. This image reading apparatus is shown in FIG.
As shown in FIG. 1, a first optical moving frame 21 with an illumination lamp that illuminates the contact transparent glass plate 20 from the lower surface, and a second optical moving frame 21 with a reflecting mirror that moves at half the speed of the first optical moving frame. And an optical moving frame 22. Furthermore, a steel wire 28 and pulleys 24 to 27 for moving the first optical moving frame 21 and the second optical moving frame 22.
Is laid out.

As shown in FIG. 6, one end of the wire 28 is fixed by a stopper 23, and is hooked on a moving pulley 24 supported by the second optical moving frame 22, and further hooked on a fixed pulley 25. It is wound around a drive pulley 26 connected to a motor 29 a plurality of times, hung on a fixed pulley 27 and returned, mounted with a first optical moving frame 21, and hung on a moving pulley 24 supported on a second optical moving frame 22. Being
The other end 31 is fixed with a stopper. Reference numeral 30 is a belt that connects the drive pulley 26 and the motor 29.

By rotating the motor 29 forward or backward, the first optical moving frame 21 and the second optical moving frame 2 are moved.
2 is moved to illuminate and scan the original, and the CCD (not shown)
The original image is read by the light receiving element.

[0005]

In the structure of the image reading apparatus using the wire as described above, the wire is bent while the optical moving frame is stationary for a long period of time, and as a result, the wire remains unmoved after a long period of stationary. There is a problem that the read image of the first document is distorted. In particular, when the image reading apparatus is required to be downsized, the diameter of the pulley tends to be small, and the problem of curling becomes noticeable.

It is possible to set the home position of the optical moving frame to a position outside the original reading range, but in this case, it is necessary to bring the optical moving frame into the original reading range for detecting the original size. , Requires extra time and power. Therefore, it is an object of the present invention to realize an image reading device capable of correcting winding of a wire before reading an original image after the optical moving frame has been stationary for a long period of time.

[0007]

The image reading apparatus of the present invention comprises a control means for controlling the rotation of the drive motor, and a time measuring means for measuring the time after the movement of the optical moving frame. The control means performs control to reciprocate a predetermined range sandwiching the home position a predetermined number of times before the document is read, on condition that the measured value of the time measuring means is equal to or more than a threshold value. It is a thing.

According to the above construction, if the time equal to or more than the threshold value has passed since the optical movement frame was moved last time,
When it is determined that it is necessary to correct the winding of the wire, the wire is reciprocated a predetermined number of times across the home position a predetermined number of times, and then the document is read. Therefore, the original can be read while the winding of the wire is eliminated, so that the original read image is not distorted.
Further, the sliding movement on the rail can be conditioned by reciprocating the optical moving frame.

It is desirable that the control means performs control to reciprocate a predetermined range sandwiching the home position a predetermined number of times when the power is turned on. “When the power is on” includes the time when the automatic shutoff (the operation of automatically turning off the power if it is not used for a certain period after the power is turned on) is released. This is because when the power is turned on, it usually takes a long time since the movement of the optical moving frame last time, so that it is necessary to correct the winding of the wire without considering the passage of time.

When the polygon motor is turned on, the control means performs control for reciprocating a predetermined range sandwiching the home position a predetermined number of times, provided that the value measured by the time measuring means is equal to or greater than a threshold value. Is preferred. When the polygon motor is turned on, the document is ready for copying after being read. Therefore, in order to prepare for a copying operation, reciprocating control is performed in advance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the accompanying drawings, using an image reading apparatus attached to a copying machine as an example. FIG. 1 is a front view showing a contact transparent glass plate 20, a first optical moving frame 21, and a second optical moving frame 22. The vicinity of the left end of the contact transparent glass plate 20 is covered with the white reference plate 20a.

The first optical moving frame 21 is a lighting lamp 21.
Inverter circuit 21a for driving b, illumination lamp 21
b, a reflection plate 21c, a PI light shielding plate 21d, and a reflection mirror 21e that reflects the reflected light from the original in a perpendicular direction. The optical path of the reflected light is shown by a chain double-dashed line. The second optical moving frame 22 includes reflecting mirrors 22a and 22b that reflect the light reflected by the reflecting mirror 21e in a right angle direction. The light emitted from the second optical moving frame 22 passes through the lens 41 and CC
It is incident on the D light receiving element 42. The CCD light receiving element 42 is
It is a one-dimensional element that extends in a direction perpendicular to the plane of the paper. The direction perpendicular to this paper surface is called the "main scanning direction", and the direction at which the optical moving frame moves at a right angle is called the "sub scanning direction".

On the left side of the second optical moving frame 22,
A photo interrupter (PI) 40 is installed. Hereinafter, the reference point of the movement of the optical moving frame is referred to as the first optical moving frame 2
1. Take the position of the reflecting mirror 21e. First optical moving frame 21
The position of the reference point when the photo interrupter 40 is shielded by the PI shading plate 21d is set to O and taken as the origin.

A home position HP of the first optical moving frame 21 is located at a position separated from the origin O by a predetermined distance (40 mm) to the right.
Let A be a position separated to the right by a predetermined distance (140 mm), and B be a position separated to the right by a predetermined distance (433 mm). The position B is the right side movement limit position of the optical movement frame. The position on the left of the origin O where the white reference plate 20a is located is defined as the shading position C. Further, the left slow-up (running) start position is D, and the position at which the document is read from the left document feeder (DF) is E. This DF reading position E becomes the left side movement limit position of the optical movement frame.

FIG. 2 is a block diagram of a control system for driving a drive motor 29 for moving the optical movement frame and a polygon motor 54 (described later). The central processing unit 51 passes the drivers 52, 53 to drive motors respectively. 29, the polygon motor 54 is driven. Reference numeral 55 denotes an operation unit of the copying machine having a copy key, a power key, and the like. FIG. 3 is a graph for explaining the locus of movement of the optical movement frame.
FIG. 3A is a diagram showing an initial correction operation when the power is turned on and when the automatic shutoff is released, and FIG. 3B is a view showing a correction operation when the normal copying is performed. Here, "correction" means
It is used to mean that the wire is wound.

FIG. 4 is a flow chart of the movement operation of the optical movement frame. This operation is performed under the control of the central processing unit 51. First, an initial correction operation is performed when the power is turned on (step S1). Specifically, FIG.
As shown in (a), set the optical movement frame to the home position HP.
To the DF reading position E which is the movement limit position, the direction is changed, and the position is shaken to the position B which is the movement limit position. That is, the optical moving frame is moved within the maximum range. After shaking to the position B, it is again shaken to the DF reading position E, returned to the origin O, and then attached to the shading position C to perform shading correction. After that, it returns to the home position HP.
Shading correction may be omitted.

Returning to the flow chart, set the timer
(Step S2), it is determined whether or not there is a request (scan) for scanning the optical movement frame for copying an original (step S3). If there is a scan request, it is determined whether the timer has passed a predetermined time (for example, 10 minutes) or more, and if it has passed, a correction operation is performed (step S5). This correction operation is shown in FIG. The optical moving frame is moved leftward by a predetermined distance (20 mm) and rightward by a predetermined distance (100 mm) from the home position HP. This operation is performed twice, the shading position C is applied to perform shading correction, the shading position is returned to the slow-up start position D, the speed is moved from this position at a constant speed, and scanning for reading an original is started (step S6). When the scanning operation is completed (step S
7) and returns to step S2.

If there is no scan request for copying the original (NO in step S3), it is determined whether or not there is a request to turn on the polygon motor 54 (step S8). The polygon motor 54 is a polygon mirror drive motor for swinging the laser light with which the photosensitive drum is irradiated. The request to turn on the polygon motor 54 is issued when only the printer is moved or when the facsimile reception operation is performed without reading the original.

If there is a request to turn on the polygon motor 54,
It is determined whether the timer has passed a predetermined time (for example, 10 minutes) or more, and if it has passed, the same correction operation as in step S5 is performed (step S10). When the printout is made, the fixing device is heated and ready for copying. Therefore, the correction operation is performed in preparation for the copying operation. Here, the locus of the optical moving frame of the present invention (FIG. 3) is compared with the locus of the conventional optical moving frame.

FIG. 5 is a locus diagram of an optical moving frame adopted in a conventional image reading apparatus, and FIG. 5 (a) is a diagram showing an initial operation such as when the power is turned on and when the automatic shutoff is released. FIG. 5 (b) is a diagram showing operations such as normal copying. The home position HP 'is 20 mm to the left of the home position HP in the embodiment of the present invention. In the initial operation of FIG. 5A, the optical movement frame is returned from the home position HP 'to the shading position C, changed in direction, and shaken to the origin O. Then, the shading correction is performed at the shading position C, and the process returns to the home position HP '.

As compared with the case of FIG. 3 (a) of the present invention, in the present invention, the maximum shaking is made, but in the conventional example, the shaking range is narrow. In the normal copying operation of FIG. 5B, the optical movement frame is returned to the slow-up start position D, and the document reading is started from here. Compared to the case of FIG. 3 (b) of the present invention, in the present invention, after making two reciprocations, the slow-up is started, but in the conventional example, the slow-up is started from the beginning.

As described above, in the embodiment of the present invention, the optical moving frame is swung a plurality of times in a wide range around the home position HP. Therefore, it is effective in correcting the winding of the wire. Further, it is possible to obtain an effect that the optical moving frame can be accustomed to sliding on the rail. The embodiment of the present invention has been described above.
The implementation of the present invention is not limited to the above-described modes.

For example, FIG. 7 is a flowchart showing a modification of the movement operation of the optical movement frame. The difference from Fig. 4 is that
Between step S8 and step S9, step S11
That is, the processing is included. As a result, if the printing operation is in progress, it is guaranteed that the correction operation will not be started even if the timer elapses for a predetermined time. In the procedure of FIG. 4, the correction operation of the optical movement frame is performed every "predetermined time" during the printing operation and even when the document is not read. Therefore, if the "predetermined time" is set to be short, the correction operation of the optical moving frame is frequently performed during a long-time printing operation (for example, when there is no scanning operation of the optical moving frame such as facsimile reception printing or printer printing). There is a problem that power is wasted and noise is generated.

In the procedure of FIG. 7, the correction operation of the optical moving frame can be prohibited during the printing operation. Therefore, since the above problem does not occur, the “predetermined time” can be set short (for example, 30 seconds). In this case, the time from the end of the printing operation until the polygon motor is turned off needs to be longer than the timer setting "predetermined time". This is because the correction operation (step S10) is always performed in consideration of the case where the "predetermined time" has not elapsed even after the printing operation is completed.

[Brief description of drawings]

FIG. 1 is a front view showing an arrangement of a contact transparent glass plate 20, a first optical moving frame 21, and a second optical moving frame 22.

FIG. 2 is a configuration diagram of a control system that drives a drive motor 29 that moves an optical moving frame and a polygon motor 54.

FIG. 3 is a graph for explaining a locus of movement of an optical movement frame. (a) is a diagram showing an initial correction operation such as when the power is turned on and when the automatic shutoff is released, and (b) is a view showing a correction operation such as during normal copying.

FIG. 4 is a flowchart of a movement operation of an optical movement frame.

FIG. 5 is a trajectory diagram of an optical moving frame used in a conventional image reading apparatus.

FIG. 6 is a wire configuration diagram for moving an optical moving frame.

FIG. 7 is a flowchart showing a modified example of the movement operation of the optical movement frame.

[Explanation of symbols]

20-contact transparent glass plate 20a White reference plate 21 First Optical Moving Frame 22 Second optical moving frame 29 Drive motor 51 Central processing unit 52,53 driver 54 polygon motor 55 Operation part

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihiro Aikawa 1-2-2 Tatamazo, Chuo-ku, Osaka-shi, Osaka Within Kyocera Mita Co., Ltd. (72) Inventor Katsuhiko Okamoto 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka No. 28 in Kyocera Mita Co., Ltd. (56) Reference Japanese Unexamined Patent Publication No. 4-269738 (JP, A) Fukui 2-44749 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) G03B 27/50 H04N 1/04-1/20

Claims (3)

(57) [Claims] 1. An image reading apparatus having a structure in which an optical moving frame is driven to rotate by a driving motor, the controlling means controlling the rotation of the driving motor, and the time after the optical moving frame is moved. And a time measuring means for measuring the time, and the control means determines a predetermined range sandwiching the home position on condition that the measured value of the time measuring means is equal to or more than a threshold value before reading the original. An image reading apparatus characterized in that it is controlled to reciprocate a number of times. 2. The image reading apparatus according to claim 1, wherein the control means performs control to reciprocate a predetermined range sandwiching the home position a predetermined number of times when the power is turned on. 3. The control means, when the polygon motor is turned on, performs control for reciprocating a predetermined range sandwiching the home position a predetermined number of times, provided that the measured value of the time measuring means is equal to or greater than a threshold value. The image reading apparatus according to claim 1, which is performed.